Showing posts with label Hofmeyr. Show all posts
Showing posts with label Hofmeyr. Show all posts

May 09, 2009

Cranial diversity in Pleistocene Africa and Europe

From the paper:
The results of the bootstrap analyses conducted in this study are compatible with the suggestion from genetic studies that living humans represent only a restricted part of past modern human variation (Underhill et al., 2000; Excoffier, 2002; Marth et al., 2003; Fagundes et al., 2007). Certainly the European and North African Upper Paleolithic samples appear to exhibit greater craniometric variability than recent human samples. Our results appear to accord with the conclusions reached by Manica et al. (2007), von Cramon-Taubadel and Lycett (2008), and Betti et al. (2009) regarding the proportional relationship between recent within-population craniometric diversity and geographic distance from eastern Africa.
Very related:

American Journal of Physical Anthropology doi:10.1002/ajpa.21080

Modern human cranial diversity in the Late Pleistocene of Africa and Eurasia: Evidence from Nazlet Khater, Pestera cu Oase, and Hofmeyr

Isabelle Crevecoeur et al.

Abstract

The origin and evolutionary history of modern humans is of considerable interest to paleoanthropologists and geneticists alike. Paleontological evidence suggests that recent humans originated and expanded from an African lineage that may have undergone demographic crises in the Late Pleistocene according to archaeological and genetic data. This would suggest that extant human populations derive from, and perhaps sample a restricted part of the genetic and morphological variation that was present in the Late Pleistocene. Crania that date to Marine Isotope Stage 3 should yield information pertaining to the level of Late Pleistocene human phenotypic diversity and its evolution in modern humans. The Nazlet Khater (NK) and Hofmeyr (HOF) crania from Egypt and South Africa, together with penecontemporaneous specimens from the Petera cu Oase in Romania, permit preliminary assessment of variation among modern humans from geographically disparate regions at this time. Morphometric and morphological comparisons with other Late Pleistocene modern human specimens, and with 23 recent human population samples, reveal that elevated levels of variation are present throughout the Late Pleistocene. Comparison of Holocene and Late Pleistocene craniometric variation through resampling analyses supports hypotheses derived from genetic data suggesting that present phenotypic variation may represent only a restricted part of Late Pleistocene human diversity. The Nazlet Khater, Hofmeyr, and Oase specimens provide a unique glimpse of that diversity.

Link

January 11, 2007

New Kostenki and South African finds in Science magazine (earliest occupation of Eurasia by modern humans)

I didn't see the papers online yet [they are now online], but from EurekAlert:
The excavation took place at Kostenki, a group of more than 20 sites along the Don River that have been under study for many decades. Kostenki previously has yielded anatomically modern human bones and artifacts dating between 30,000 and 40,000 years old, including the oldest firmly dated bone and ivory needles with eyelets that indicate the early inhabitants were tailoring animal furs to help them survive the harsh climate.
From the New York Times:
An international team of researchers reported today that the age of the South African skull, which they dated at about 36,000 years old, coincided with the age of and closely resembled the skulls of humans who were then living in Europe and the far eastern parts of Asia, even Australia.
The discovery of these resemblances lends some support to the idea that I have expressed previously that only a subset of modern humans (which I have called Afrasians) was responsible for the colonization of Eurasia. At the time frame in question, these resemblances would have been marked, since (i) intermixture with pre-existing populations (such as "Paleoafricans" or pre-moderns in Europe) did not have time to take place yet, and (ii) racial differentiation had only just begun. This paragraph says it all:
Because the Bushmen are well represented in the more recent archaeological record, Dr. Harvati said, they were expected to bear a close resemblance to the Hofmeyr skull. Instead, the skull was found to be quite distinct from all recent Africans, including the Bushmen, she said, and it has “a very close affinity” with fossil specimens of Europeans living in the Upper Paleolithic, the period best known for advanced stone tools and cave art.

“Much to my amazement,” Dr. Grine said in an interview, “the skull linked very closely with those from Europe at the time and not with South African remains 15,000 years on.”
The dissimilarity to recent Africans of the Hofmeyr skull can be easily explained if it is understood that recent Africans are not only descended from the "Afrasians" that I have spoken of, but also from the older "Paleofricans" whose existence can be inferred both by genetics (human mtDNA and Y-chromosomes are older than the ~40kya mark) and paleoanthropology (modern humans such as Omo and Herto are 100-200kya old).

It also stresses the idea that contrary to popular treatments such as Spencer Wells' Journey of Man, the appearance of African hunter-gatherers such as the Khoi-San should not be used as a model of what mankind's earliest African ancestors looked like.

Late Pleistocene Human Skull from Hofmeyr, South Africa, and Modern Human Origins

F. E. Grine et al.

The lack of Late Pleistocene human fossils from sub-Saharan Africa has limited paleontological testing of competing models of recent human evolution. We have dated a skull from Hofmeyr, South Africa, to 36.2 ± 3.3 thousand years ago through a combination of optically stimulated luminescence and uranium-series dating methods. The skull is morphologically modern overall but displays some archaic features. Its strongest morphometric affinities are with Upper Paleolithic (UP) Eurasians rather than recent, geographically proximate people. The Hofmeyr cranium is consistent with the hypothesis that UP Eurasians descended from a population that emigrated from sub-Saharan Africa in the Late Pleistocene.

Link

Early Upper Paleolithic in Eastern Europe and Implications for the Dispersal of Modern Humans

M. V. Anikovich et al.

Radiocarbon and optically stimulated luminescence dating and magnetic stratigraphy indicate Upper Paleolithic occupation—probably representing modern humans—at archaeological sites on the Don River in Russia 45,000 to 42,000 years ago. The oldest levels at Kostenki underlie a volcanic ash horizon identified as the Campanian Ignimbrite Y5 tephra that is dated elsewhere to about 40,000 years ago. The occupation layers contain bone and ivory artifacts, including possible figurative art, and fossil shells imported more than 500 kilometers. Thus, modern humans appeared on the central plain of Eastern Europe as early as anywhere else in northern Eurasia.

Link